Handkerchief (if you get stuck out in cold weather your nose will run like a faucet!) general purpose rag, hand towel, emergency toilet paper,neck or face scarf, tourniquet,Bandage/Ace Bandage,patching material for torn clothing or backpacks, strainer for salty water,protection while grabbing hot pot handles, and a dish rag
A typical cotton bandanna only weighs an ounce, so for a small amount of weight, you get a lot of function. If you need to clean and re-use it, just rinse it in a stream, lake or river. To sterilize it or to remove grease, boil it in water for a couple of minutes and you're ready to go.Also, carry your bandanna in a zip lock bag or other waterproof container to keep it dry until needed.